1. Field of the Invention
The present invention relates to a dehydrating method of a drum type washing machine, and more particularly, to a dehydrating method of a drum type washing machine for precisely detecting a single load for a dehydrating cycle to effectively dehydrate.
The present invention relates to a dehydrating method of a drum type washing machine for distinguishing a single load into a long single load and a short single load based on a length of laundry when the laundry is unfolded in a case when the laundry inserted into a drum of the drum type washing machine is the single load to effectively dehydrate.
The present invention relates to a drum type washing machine for detecting a single load to distinguish the detected single load into a long single load and a short single load so that effective dehydrating is carried out.
2. Discussion of the Related Art
Generally, a washing machine is an apparatus for washing laundry to separate contaminants from the laundry such as clothes, bedclothes, or the like (hereinafter referred to as “laundry”) using washing water and detergent during a washing cycle, a rinsing cycle, a dehydrating cycle, and a drying cycle.
FIG. 1 is a sectional view illustrating the internal structure of a conventional drum type washing machine.
The conventional drum type washing machine, as shown in FIG. 1, includes a cabinet 2, a tub 8, a drum 10, a lifter 12, and a motor 14.
The cabinet 2 forms the whole external appearance of the conventional drum type washing machine, the tub 8 accommodates washing water and is installed in the cabinet to be buffered by a spring 4 and a damper 6. The drum 10 accommodates the laundry and is disposed to rotate in the tub 8. In the outer circumference of the drum 10, a plurality of water holes 10A are formed and the washing water is introduced into a space defined by the drum 10 and the tub 8.
Moreover, in the inner wall of the drum 10, the lifter 12 is installed to lift the laundry up to a predetermined height such that the laundry drops during the rotation of the drum 10.
A motor is provided to transmit the rotation force to the drum 10. Recently, a directly coupling type motor, in which the motor 14 is mounted in the rear side of the tub 8, is widely employed.
Meanwhile, the conventional drum type washing machine further includes a cabinet cover 16 installed in the front side of the cabinet 2 and having a laundry entrance 16A formed in the central area of the cabinet 2, and a door 18 pivotally installed to the cabinet cover 16 to open and close the laundry entrance 16A.
The conventional drum type washing machine further includes a control panel having a controller for controlling the conventional drum type washing machine, and a hall sensor 22 installed at a side of the motor 14 to detect the rotation speed of the motor (RPM) and a rotation angle.
In the upper side of the cabinet 2, a top plate 24 is mounted. In the lower side of the top plate 24, a water supply 30, including a water supplying hose 26 and a water supplying valve to supply washing water into the tub 8 from an external water source, is installed. In a water supplying passage of the water supplying device 30, a detergent supplying device 32 for supplying detergent together the washing water supplied into the tub 8 is installed to communicate with the tub 8.
In the lower side of the tub 8, in order to exhaust the washing water used during the washing cycle and the rinsing cycle to the exterior, is installed an exhaust device 40 including an exhausting hose 34, an exhausting pump 36, and an exhausting bellows 38.
The hall sensor 22 generates a pulse signal according to the positional change of the motor 14, and RPM and a rotation angle of the motor 14 are measured using the pulse signal.
Operation of the conventional drum type washing machine will be described.
Firstly, the door 18 is opened to insert the laundry into the drum 10 through the laundry entrance 16A. After sealing the laundry entrance 16A by closing the door 18, a proper quantity of detergent is inserted into the detergent supplying device 32 according to the kind and quantity of the laundry inserted into the drum 10. Naturally, the supply of the detergent may be carried out manually or may be automatically controlled.
When the conventional drum type washing machine 1 starts to operate, the quantity of the laundry inserted into the drum 10 is detected, based on the detected quantity of the laundry, a washing method such as the washing course, the washing time, the level of the water to be supplied, the quantity of the detergent, and the like is determined, and the conventional drum type washing machine 1 is driven by the washing method.
In other words, when the washing water is supplied into the tub 8 by the water supplying device 30, the detergent inserted into the detergent supplying device 32 is mixed with the washing water supplied by the water supplying device 30 and is also supplied into the tub 8.
After the washing water is accommodated in the tub 8 to a predetermined level, and when the drum 10 is rotated by the motor 14, the laundry is lifted up to a predetermined height by the lifter 12 installed in the drum 10 and then drops due to gravity. At this time, due to the falling force of the laundry and the interaction of the laundry with the washing water, the contaminants are separated from the laundry.
When the washing cycle is completed, the contaminated washing water in the tub 8 is exhausted out of the conventional drum type washing machine through the exhaust device 40.
After this, the conventional drum type washing machine 1 performs the rinsing cycle, for removing bubbles and detergent remaining in the laundry, several times. In other words, clean washing water is supplied into the tub 8 by the water supplying device 30 up to the predetermined level and the drum 10 is rotated by the motor 14 so that the laundry is rinsed and after that the used washing water is exhausted out through the exhaust device 40.
When the several rinsing cycles are completed, the drum 10 is rotated at a high speed by the motor 14 to dehydrate the laundry, and if a drying device is provided in the conventional drum type washing machine 1, the drying cycle is also carried out.
FIG. 2 is a graph illustrating RPM of the motor with respect to time in the dehydrating cycle of the conventional drum type washing machine. As shown in the graph, the dehydration is carried out by controlling the RPM of the motor.
The dehydrating method of in the conventional drum type washing machine will be described as follows.
The dehydrating method of the conventional drum type washing machine includes the steps of (1) detecting a quantity of laundry for determining an optimal dehydrating time or a dehydrating RPM, (2) detecting eccentricity for determining the starting of a main dehydration or untangling of the laundry, and (3) controlling the motor 14 at a high speed after the steps (1) or (2).
As shown in FIG. 2, when the washing cycle or the rinsing cycle is completed, sequentially, the step (1) is carried out twice (time period a) and the step (2) is carried out at least once (time period b).
During the step (1) (time period a), the motor 14 is accelerated to a predetermined RPM, and when the RPM reaches the first predetermined RPM RPM1, the first predetermined RPM RPM1 is maintained and the motor is turned off.
At this time, a duty value of the pulse width modulation (PWM) when a static speed is maintained at the first predetermined RPM RPM1 and a surplus angle after turning off of the motor 14 are measured to detect the quantity of the laundry.
During the step (2) (time period b), the motor 14 is accelerated such that the RPM reaches a second predetermined RPM RPM2 greater than the first predetermined RPM RPM1, and when the RPM reaches the second predetermined RPM RPM2, the second predetermined RPM RPM2 is maintained and after that the motor 14 is turned off. At this time, using an RPM ripple when a static speed is maintained at the second predetermined RPM RPM2, the eccentricity of the laundry is detected.
The above-mentioned conventional drum type washing machine 1, performs untangling of the laundry (time period c) for the removal of the eccentricity and performs the step (2) (time period b′).
On the other hand, when the eccentricity detected during the initial eccentricity detection (time period b) or after the untangling of the laundry (time period c) is lower than a predetermined value, the conventional drum type washing machine 1 drives the motor 14 at a third predetermined RPM RPM3, higher than the second predetermined RPM RPM2, to dehydrate the laundry using the centrifugal force at a high speed.
The above-mentioned main dehydration (time period d) consists of an optimal dehydrating time based on the quantity of the laundry detected during the step (1) (time period a) or the dehydration RPM.
However, according to the dehydrating method of the conventional drum type washing machine, when the laundry inserted into the drum 10 is a single load of a single piece of laundry, time for detecting the eccentricity (time period b) and time for untangling the laundry (time period c) are remarkably increased so that the starting time of the main dehydrating step is significantly shortened.
In other words, the laundry inserted into the drum 10 is divided into a big quantity load, a medium quantity load, and a small quantity load based on the quantity of the laundry. The small quantity load includes a single load consisting of a single piece of laundry.
Naturally, in this patent application, the single load means that the number of pieces of laundry is one. The single load may include other laundry such as handkerchief that does not influence the load substantially.
The single load may be divided into a long single load and a short single load according to a length when the laundry is unfolded. The long single load is a single load such that when the laundry is unfolded its length is greater than a radial directional height of the drum 10 and the short single load is a single load such that when the laundry is unfolded its length is less than the radial directional height of the drum 10.
In more detail, the long single load is a piece of laundry which is longer than a half of the inner circumferential length of the drum 10 when the laundry closely contacts and is completely unfolded on the inner circumference, and the short single load is a piece of laundry which is shorter than a half of the inner circumferential length of the drum 10.
Thus, when the long single load is unfolded to be long on the inner circumference of the drum 10 in the circumferential direction during the untangling of the laundry, the eccentricity is removed and the dehydration can be performed. However, the short single load is always unbalanced in the drum even when the untangling of the laundry (time period c) and the detection of the eccentricity (time period b) are performed several times.
Meanwhile, in the dehydrating method of the conventional drum type washing machine, when the eccentricity is not removed even after repeating the untangling (time period c) and the detection of the eccentricity (time period b) a predetermined number of times, the main dehydrating step is forcibly performed.
Thus, since unnecessary untangling (time period c) and the detection of the eccentricity (time period b) are repeated a predetermined number of times in a case of the short single load, entire time for the dehydration is increased in the conventional drum type washing machine 1, so that it may cause consumers to complain. It is because the untangling and the detection of the eccentricity are meaningless in the case of the short single load.
Therefore, according to the dehydrating method of the conventional drum type washing machine, in a case of a single load, since the dehydration of the laundry is not processed by the optimal dehydrating method, vibration of the conventional drum type washing machine 1 is more serious during the main dehydrating step, and the conventional drum type washing machine 1 vibrates seriously.
Even in a case of the single load in the conventional drum type washing machine, during the untangling of the laundry (time period c), the rotation direction of the drum 10 is reversed a predetermined number of times to reduce the eccentricity of the laundry. Thus, like that the drum 10 rotates slow or stops, since a time period when the untangling is not performed occurs, the untangling is inferior in effect and time is longer even in the case of the single load. Naturally, according to the length of the single load, the untangling time may be meaningless.
Moreover, in the dehydrating method of the conventional drum type washing machine, even in the case of the single load, the detection of the eccentricity (time period b) is automatically started when the untangling (time period c) is processed a predetermined number of times regardless of the eccentricity of the laundry. Thus, in the case of the single load, since the detection of the eccentricity is not carried out at a proper time, times for detecting the eccentricity are increased. Naturally, according to the length of the single load, the time of detecting the eccentricity may be meaningless.